One of the unlikeliest racers in a field full of mongrels is Shaun Rainford’s 1956 ‘bathtub’ Metropolitan, built for Goodwood Revival in the spirit of the HRDC formula of ‘organised mayhem in district-nurse tackle’. It was born from a well-lubed conversation with HRDC founder Julius Thurgood about the most inappropriate racing car. Rainford’s CCK operation – which has also fielded a Volga, after all – was up to the challenge. A donor car was found at an auction in Kent, £1200 paid, and the build began.

So, picking a car with a joke silhouette is a good start. How do you make it go fast? Start with an MGB engine. HRDC/St Mary’s spec allows a 25% increase in capacity, so instead of the standard 1489cc B-series it runs an 1860 with steel crank and rods, JE forged pistons, billet flywheel and a big-valve head.

‘The old engine was putting out 176bhp on split Webers,’ says CCK’s historian and master of the rolls Daniel Lackey. ‘With help from Doug Smith the new engine is softer than the old, with 150bhp, but there’s more torque so there’s more punch out of corners. Max power is now at 6750rpm and I change up at 6500. With the old engine we revved to 8000rpm but reliability was a problem.’

‘Before the Revival they told us we couldn’t run the split Webers,’ adds Rainford. ‘So we had to change to a single 48. It went straight from the rolling road to Goodwood.

All this drives through a Midget axle with extra-strong halfshafts, tied in with a trick Watt’s linkage, and the gearbox is now a close-ratio MGB four-speeder rather than the original three-on-a-tree. Solid bronze bushes up front – and eaten at a prodigious rate – allow for a bit of negative camber. Shaun says the handling is ‘diabolical’.

‘It turns in lovely, but as you put the power down the outside rear spring collapses and it lifts the inside front. It just wants to fall over. At Woodcote I couldn’t see the apex because the wing was so high in the air.’ In the rain it’s terrifying to watch, the car’s short wheelbase making it incredibly twitchy. The Nash’s other party trick is lifting both inside wheels.

‘It just will not slide, so it goes up on two wheels. Then you’re off the power losing time as you wait for it to come back down.’

It made its debut in the 2012 Revival, when it blew up in qualifying but finished both races, Shaun sharing with former BTCC star John Cleland. Given Cleland’s distaste for his two-wheeling 1995 BTCC Cavalier, what does he make of the Nash?

‘He thinks it’s completely bonkers.’

But this crowd-pleaser has actually become quite effective: ‘All I wanted from Revival was to get it in the top 15,’ Shaun says, ‘and we managed that.’ He again shared the driving with Cleland for a 14th-place aggregate finish.

And, unlikely racer though it is, someone got there before them. Lackey found a period pic of a convertible storming Paddock Bend at Brands Hatch. If you know more about VGW 748, please get in touch with CCK.